Ultrasonic carburetor



Oct. 13, 1959 F. FRUENGEL ULTRASONIC CARBURETOR Filed April 26, 1955 INVEN TOR.

fie/vA/tfezxwaz United States Patent Ofiice 2,908,443 Patented 13, 1959ULTRASONIC CARBURETOR Frank Fruengel, Hamburg-Rissen, GermanyApplication April 26, 1955, Serial No. 503,950

Germany June 7, 1949 Public Law 619, August 23, 1954 Patent expires June7, 1969 6 Claims. (Cl. 239-102) This invention relates to enginecarburetors and more particularly is concerned with the application ofultrasonic vibration for intensifying atomization of fuel mixtures.

As well known in the art, it is possible to atomize by intensiveultrasonic vibration liquids whenever the amplitude of vibration of theultrasonic transducer surface is so great that the thereby producedalternating pressure causes cavitation phenomena within the liquid undertreatment. By readily evaporating liquids such as, for instance, motorfuel gasoline, such cavitating action begins at ultrasonic energyoutputs of one watt per square centimeter. Since the fuel dispersion anddroplet distribution created by conventional carburetors is notcompletely satisfactory, particularly not in high efficiency engines andfor low fuel consumption, the application of more intensive atomizationmeans is very desirable.

Therefore, it is the primary object of this invention to provide acarburetor which utilizes ultrasonic vibration for better atomization ofthe fuel mixture.

Other objects and advantages of the invention will become apparent fromthe following detailed description of some preferred embodiments whenread in connection with the accompanying drawing in which Fig. 1 is adiagrammatic longitudinal section through a preferred form of acarburetor according to this invention;

Fig. 2 is a diagrammatic showing of a carburetor nozzle body providedwith a coil for ultrasonic excitation;

Fig. 3 shows diagrammatically a carburetor nozzle body of modifiedconstruction also provided with a high fre quency coil;

Fig. 4 is a cross-section on the line 44 of Figs. 2 and 3 showing alongitudinal slot in the nozzle body filled with insulating material forreducing eddy currents;

Fig.5 is a diagrammatic showing of an arrangement employing anultrasonic generator actuated by the exhaust gases of the engine.

Referring to Fig. 1 of the drawing, there will be noted inlet tube 1through which, controlled by valve {2, engine fuel at a desired rateenters in droplets into the carburetor. These fuel droplets fall uponthe carburetor plate 3 which actually is an ultrasonic transducervibrating at ultrasonic frequency. This vibrator causes completeatomization of the fuel which then is carried by the intake suction inthe intake manifold 4 under admixture of air, as in conventionalcarburetors, into the cylinders ofthe internal combustion engine. Theexcitation of transducer 3 is provided by electric connection to a highfrequency circuit not shown.

In an embodiment as shown in Fig. 2, the dispersing action of a commonfuel nozzle is retained and ultrasonic atomization is additionallyapplied for intensifying the fuel mixture preparation. To achieve thisend according to this invention, the nozzle body 5 is preferably made ofmagnetostrictive material. When excited by ultrasonic frequency, thenozzle 6 vibrates together with nozzle body 5. Excitation is derivedfrom coil 7 which is fed from a high frequency generator 8.Premagnetization, if necessary, is effected by coil 9 energized from abattery 10. Ultrasonic influence is thus substantially restricted to thesmall area of nozzle 6. In order to obtain a larger area for ultrasonicaction, or better, a larger atomization area, an arrangement accordingto Fig. 3 can be employed. It will be noted that here the nozzle 6.has afunnel-like extension 11 in front of'nozzle 6. Such shape with itsincreased outlet area causes additional atomizing of the fuel, becauseultrasonic energy is radiated in the direction of the arrows and thusinto the combustible mixture 12. For highest efficiency it is advisableto calculate the configuration of the funnel outlet according toacoustic laws and give it a shape that assures within the combustiblemixture the desirable direction of ultrasonic radiation. A furtherincrease in effectiveness of atomization can be gained by designingextension 11 so that its natural frequency is in resonance With theultrasonic frequency imparted to nozzle body 5.

In order to avoid unnecessary eddy current losses in nozzle body 5 it isadvisable to employ a construction in which the nozzle body is partly orcompletely slotted as indicated at 13 in Figs. 2 and 3 and as shown insection in Fig. 4-. This slot is preferably filled with an insulatingmaterial. The nozzle body in this instance is preferably made from amaterial as generally used for the construc tion of magnetostrictivedevices, such as 'Invar or nickel. It will be understood that forexciting the nozzle it is also possible to employ a suitable separatetransducer as commercially obtainable. Moreover, the disclosedconstruction lends itself to a design in which the nozzle proper is ofanother material as the nozzle body. This is to be preferred, because athigh loading known magnetostrictive materials are too soft to Withstandthe great forces imposed on them by cavitation phenomina. Thus it isadvisable to use for the nozzle 6 a hard metal, such as the tungstencarbide material known under the trademark Widia, or the like, and suchmaterial is referred to when reciting hard metal in the specificationand the claims. However, in such construction it is of importance thatthe nozzle is intimately joined to the nozzle body 5 by brazing orotherwise in order to assure ultrasonic passover from one part to theother without substantial losses.

Still another method of obtaining the benefit of ultrasonic atomizationof engine fuels is depicted in Fig. 5. Here an ultrasonic generatoractuated by compressed air or by the pressure of the exhaust gases ofthe engine is employed. The exhaust gases leave outlet 14 under highpressure, impinge upon the edges of resonator 15 and excite theresonance space 16 to forceful ultrasonic vibration in a manner wellknown in the art. Ultrasonic vibration spreading in directions of thearrows reaches to a considerable extent the reflector 17 and isconverged by this reflector so that ultrasonic energy is concentrated at18 in front of nozzle 6. The combustible mixture entering through nozzle6 is thus exposed to high-amplitude ultrasonic vibration and is atomizedby this vibratory action. g

In order to prevent the exhaust gases from entering the carburetorchamber and disturb orderly progression of the pressure phases withinthis chamber or cause premature ignition, it is advisable to arrange theultrasonic generator in a space separated from the carburetor by apartition 19 provided with an aperture 20. This aperture in turn ispreferably closed by a diaphragm 21 of sheet mica or aluminum foil, oranother material having little mass and high tensile strength and beingvery thin in order to avoid as much as possible loss of ultrasonicenergy. The separation of the ultrasonic source from the carburetorchamber may take other forms and very effective is a diaphragmconsisting of two foil sheets of material suitable spaced whereby thespace therebetween is filled with a suitable gas, preferably underpressure, so that the diaphragm unit assumes the shape of a lens andassists in focusing the penetrating ultrasonic radiation in point 18.

Practical experiments have shown that by applying ultrasonic atomizationas provided by this invention, the droplet size of the so atomizedengine fuel is considerably smaller than after dispersion by acarburetor of conventional construction.

The present invention has been described as utilized for atomizingengine fuel, but it is to be understood that this is only one field ofapplication and that its teachings can be made useful for other purposesas well, for instance, in connection with spraying devices for lacquersand paints and in other fields where atomization of liquids into finemists is essential.

Ultrasonic vibration causes not only atomization of liquid droplets, butit becomes also effective in condensing fogs and mists when thevibration is of the proper condensing frequency. Thus it is possible toatomize liquids into a finely distributed spray by the means shown inFigs. 1 to 4 and then to condense this spray by an arrangement somewhatsimilar to that shown in Fig. 5. Such procedure can be made useful inapplying finishes to surfaces by spraying, in that ultrasonic energyconcentration is focused at a point near the surface to which the finishis to be applied and which lies within the spray. Then, if theultrasonic vibration is of the proper frequency the spray will readilybe condensed on the surface. When using compressed air spray guns ofconventional construction it is possible to drive an ultrasonicgenerator as shown in Fig. 5 from the same compressed air source and toarrange this generator adjacent to the spray nozzle such that theultrasonic radiation emanating from it is concentrated at a point wherequick condensation of the sprayed liquid is desirable.

From this description of a few embodiments of the invention it willbecome apparent that other modifications are possible which do notdepart from the true spirit and scope of this invention as limited onlyby the appended claims.

What is claimed is:

1. In a carburetor for ultrasonic atomization of engine fuel, an intakenozzle body of magnetostrictive material being provided with alongitudinal slot filled with in sulating material, a nozzle ofnon-magnetostrictive hard metal intimately joined to said nozzle bodyfor free passover of ultrasonic energy from said nozzle body to saidnozzle, a coil surrounding said nozzle body and adapted to be energizedby high frequency electric energy for imparting magnetostrictivevibration to said nozzle body and nozzle whereby to atomize engine fuelpassing therethrough, and means for connecting said coil to a highfrequency electric energy source.

2. In a carburetor for ultrasonic atomization of engine fuel, an intakenozzle body of magnetostrictive material being provided with alongitudinal slot filled with insulation material, a nozzle ofnon-magnetostrictive hard metal intimately joined to said nozzle bodyfor free passover of ultrasonic energy from said nozzle body to saidnozzle, said nozzle having an outward extension for directing ultrasonicenergy radiation into the space in front of said nozzle, a coilsurrounding said nozzle body and adapted to be energized by highfrequency electric energy for imparting magnetostrictive vibration tosaid nozzle body and nozzle whereby to atomize engine fuel passingtherethrough, and means for connecting said coil to a high frequencyelectric energy source.

3. In a carburetor for ultrasonic atomization of engine fuel, an intakenozzle body of magnetostrictive material being provided with alongitudinal slot filled with insulation material, a nozzle ofnon-magnetostrictive hard metal intimately joined to said nozzle bodyfor free passover of ultrasonic energy from said nozzle body to saidnozzle, said nozzle having an outward extension whose natural frequencyis in resonance with the ultrasonic frequency imparted to said nozzlebody, a coil surrounding said nozzle body and adapted to be energized byhigh frequency electric energy for imparting magnetostrictive vibrationto said nozzle body and nozzle whereby to atomize engine fuel passingtherethrough, and means for connecting said coil to a high frequencyelectric energy source.

4. In a device for ultrasonic atomization of a liquid, an intake nozzlebody of magnetostrictive material being provided with a longitudinalslot filled with insulating material, a nozzle of non-magnetostrictivehard metal intimately joined to said nozzle body for free pass-over ofultrasonic energy from said nozzle body to said nozzle, a coilsurrounding said nozzle body and adapted to be energized by highfrequency electric energy for imparting magnetostrictive vibration tosaid nozzle body and nozzle whereby to atomize a liquid passingtherethrough, and means for connecting said coil to a high frequencyelectric energy source.

5. In a device for ultrasonic atomization of a liquid, an intake nozzlebody of magnetostrictive material being provided with a longitudinalslot filled with insulation material, a nozzle of non-magnetostrictivehard metal intimately joined to said nozzle body for free pass-over ofultrasonic energy from said nozzle body to said nozzle, said nozzlehaving an outward extension for directing ultrasonic energy radiationinto the space in front of said nozzle, a coil surrounding said nozzlebody and adapted to be energized by high frequency electric energy forimparting magnetostrictive vibration to said nozzle body and nozzlewhereby to atomize a liquid passing therethrough, and means forconnecting said coil to a high frequency electric energy source.

6. In a device for ultrasonic atomization of a liquid, an intake nozzlebody of magnetostrictive material being provided with a longitudinalslot filled with insulation material, a nozzle of non-magnetostrictivehard metal intimately joined to said nozzle body for free pass-over ofultrasonic energy from said nozzle body to said nozzle, said nozzlehaving an outward extension whose natural frequency is in resonance withthe ultrasonic frequency imparted to said nozzle body, a coilsurrounding said nozzle body and adapted to be energized by highfrequency electric energy for imparting magnetostrictive vibration tosaid nozzle body and nozzle whereby to atomize a liquid passingtherethrough, and means for connecting said coil to a high frequencyelectric energy source.

References Cited in the file of this patent UNITED STATES PATENTS1,939,302 Heaney Dec. 12, 1933 2,414,494 Vang Jan. 21, 1947 2,436,570Hancock Feb. 24, 1948 2,453,595 Rosenthal Nov. 9, 1948 2,454,900 VangNov. 30, 1948 2,532,554 Jocck Dec. 5, 1950 2,704,535 Magui et al Mar.22, 1955

